The importance of properdin in disease has also been demonstrated using properdin-deficient mice disease models of asthma (41), arthritis (42–44), abdominal aortic aneurysm formation (45), Streptococcus pneumoniae-induced septicemia (46), renal ischemia reperfusion injury (47), 5-fluorouracil-induced small intestinal mucositis (48), zymosan-induced non-septic shock (49) and aHUS (50), where the properdin-deficient mice were more protected from the disease vs. wild type animals [reviewed in (14)]. Here, CFP is linked to Arthritis.